The present invention relates to vibration monitoring for aircraft engines and, more particularly, to a computer-based system for accessing a raw vibration signal from the aircraft engine.
Typical commercial aircraft engines have accelerometers and an associated signal conditioning system to monitor engine health and provide an indication of vibration to the flight crew. Most current aircraft vibration monitoring systems have the vibration monitoring computer located in the electronics bay in the body of the aircraft, and the accelerometers located on the engine. Initial signal conditioning units, such as amplifiers, may be located on the engine, in the strut, or in the aircraft electronics bay. The vibration monitoring computer, which is a signal processing unit that performs functions such as filtering the signals to determine the synchronous vibration, are typically located in the aircraft electronics bay. The output of this signal processor is a greatly simplified representation of the original signal. A typical output would only be the 1/rev vibration amplitude for each of the engine rotors, for example the 1/rev LP (low pressure) and HP (high pressure) values reported once per second. The much more complicated original vibration signal would contain this information, as well as responses at many other frequencies, such as harmonics of the 1/rev, rotor blade passing frequencies, and rolling element bearing passing frequencies.
On some engine and aircraft systems, however, this signal processor is located on the engine or the engine pylon. The advantage to mounting the vibration monitoring computer on the engine or pylon compared to the aircraft electronics bay is that the system is typically lighter in weight and the vibration signals are subject to less noise. However, if a vibration problem arises where access to the raw vibration signal is needed in order to do a proper diagnosis of the cause, some action would be required, such as running a wire from the signal processing computer on the engine, through the wing to the cabin of the aircraft, to allow access to the raw data. Thus, when the vibration monitoring computer is located on the engine, it can be difficult, if not outright impossible, to access the raw waveform data for troubleshooting.
It would be desirable to provide access the raw vibration signal from a vibration monitoring computer, particularly when the vibration monitoring computer is mounted on or near the engine, without the need for extraordinary measures as currently required by the existing art.